This contract will support the re-competition of the Influenza Research Center (IRC). The IRC is an integral part of the Influenza Program and represents the largest single component of the program. It was begun in 1974 as one of the recommendations of the eight Influenza Workshops sponsored by NIAID. The IRC has carefully characterized the impact of influenza in the community and is now prepared to concentrate efforts in the testing and evaluation of measures to control influenza virus infections.